Ind. Code § 6-8.1-5-2
(a) Except as otherwise provided in this section, the department may not issue a proposed assessment under section 1 of this chapter more than three (3) years after the latest of the date the return is filed, or either of the following:
(g) If any part of a listed tax has been erroneously refunded by the department, the erroneous refund may be recovered through the assessment procedures established in this chapter. An assessment issued for an erroneous refund must be issued:
(h) If, before the end of the time within which the department may make an assessment, the department and the person agree to extend that assessment period, the period may be extended according to the terms of a written agreement signed by both the department and the person. The agreement must contain:
(2) a statement that the person agrees to preserve the person's records until the extension terminates.
The department and a person may agree to more than one (1) extension under this subsection.
(i) If a taxpayer's federal taxable income, federal adjusted gross income, or federal income tax liability for a taxable year is modified due to a modification as provided under IC 6-3-4-6 (c) and IC 6-3-4-6 (d) (for the adjusted gross income tax), or a modification or alteration as provided under IC 6-5.5-6-6 (c) and IC 6-5.5-6-6 (e) (for the financial institutions tax), then the date by which the department must issue a proposed assessment under section 1 of this chapter for tax imposed under IC 6-3 is extended to six (6) months after the date on which the notice of modification is filed with the department by the taxpayer.
As added by Acts 1980, P.L.61, SEC.1. Amended by P.L.73-1983, SEC.16; P.L.82-1983, SEC.11; P.L.76-1985, SEC.6; P.L.335-1989(ss), SEC.19; P.L.347-1989(ss), SEC.18; P.L.2-1991, SEC.55; P.L.28-1997, SEC.26; P.L.181-1999, SEC.6; P.L.192-2002(ss), SEC.143; P.L.131-2008, SEC.28; P.L.182-2009(ss), SEC.251; P.L.242-2015, SEC.36; P.L.149-2016, SEC.31; P.L.198-2016, SEC.58; P.L.197-2016, SEC.76; P.L.247-2017, SEC.26; P.L.257-2017, SEC.15; P.L.256-2017, SEC.86.